We present experimental results for adsorption of methane and ethane in activated carbon (AC610) and activated carbon fibers (KF1500 and A10) at pressures up to 10 MPa and temperatures between 313.15 and 373.15 K from a modified direct weighing densimeter. The general features of high-pressure adsorption in these carbons are discussed. We also report grand canonical Monte Carlo simulations and nonlocal density functional theory calculations to model methane adsorption in carbons. By combining these calculated results with the pore size distribution calculated from previously obtained data, we are able to compare our simulation and theoretical results with those of ourmore » experiments. 23 refs., 9 figs.« less

We present a detailed comparison between experimental adsorption measurements and the excess adsorption predicted by the Ono-Kondo equations. The study was done for high-pressure adsorption of methane above the critical point on microporous adsorbents. The experimental adsorption isotherms of CH{sub 4} on the activated carbon CNS-201 as well as others are compared with theory over the temperature range 243-333 K and for pressures up to 16 MPa. Extension of the model to zeolites is also discussed. 20 refs., 20 figs., 1 tab.

Adsorption isotherms of methane and carbon dioxide on two kinds of Australian coals have been measured at three temperatures up to pressures of 20 MPa. The adsorption behavior is described by three isotherm equations: extended three-parameter, Langmuir, and Toth. Among these, the Toth equation is found to be the most suitable, yielding the most realistic values of pore volume of the coals and the adsorbed phase density. Also, the surface area of coals obtained from CO{sub 2} adsorption at 273 K is found to be the meaningful parameter which captures the CO{sub 2} adsorption capacity. A maximum in the excessmore » amount adsorbed of each gas appears at a lower pressure with a decrease in temperature. For carbon dioxide, after the appearance of the maximum, an inflection point in the excess amount adsorbed is observed close to the critical density at each temperature, indicating that the decrease in the gas-phase density change with pressure influences the behavior of the excess amount adsorbed. In the context of CO{sub 2} sequestration, it is found that CO{sub 2} injection pressures of lower than 10 MPa may be desirable for the CH{sub 4} recovery process and CO{sub 2}-holding capacity.« less